JBL L100T restoration

[Mikesignal]

Hi all. I just got a pair of JBL L100t's. I have fixed the tweeters and installed new foam on the woofers. I played some music through them using a CD player and a 20 watt receiver . At first they sounded good, then all of a sudden they sound very flat. Thinking I need to replace the capacitors in the crossover next. Am I on the right track? any other advice? thanks

[grumpy]

Well, congrats and condolences. An unfortunate start for a fairly reasonable sounding system.

Can you define 'flat' a bit more? e.g., no bass or no highs?
Just one speaker or both?
Can you put your ear to the drivers and make sure each one is making sound?
Anything else to test them with (or verify the receiver is not the issue... loudness switch on/off? ...)
Did they change suddenly (as it seems you've described), or have you just realized they're not what you expected?

I personally wouldn't start with shotgunning parts, unless you suspect damage.

[BMWCCA]

Obviously this has little to do with a sudden change in sound, but you need more power.

And then, how loud were you playing them?

Under-powering those tweeters at loud volume will distort and blow them. That might account for a flat sound. In which case you should have used more power? Take a cardboard tube (paper towel, wrapping paper) and put it to your ear and the individual drivers to isolate and determine if they are all working. What did you have to "fix" on the speakers before?

Good Luck

[Mikesignal]

Obviously this has little to do with a sudden change in sound, but you need more power.

And then, how loud were you playing them?

Under-powering those tweeters at loud volume will distort and blow them. That might account for a flat sound. In which case you should have used more power? Take a cardboard tube (paper towel, wrapping paper) and put it to your ear and the individual drivers to isolate and determine if they are all working. What did you have to "fix" on the speakers before?

Good Luck

Thanks for the replies -- I double checked the tweeters and they are not working. They were working after I repaired them- I replaced the wire from the diaphragm to the terminal, as per previous threads..... I'm wondering of they are blown from being underpowered at loud volume. I did crank up the 20 watt Sansui a little loud which did produce some distortion. (needs a recap)

[Riley Casey]

Hate to say it after the fact but it's actually easier to damage a speaker rated at 100 watts with a 20 watt amp than with a 200 watt amp. Music by its very nature requires the most power to produce low frequency sounds. Woofers are usually the part of the speaker made to absorb the most power while tweeters since they aren't really required to do the heavy lifting require and can withstand the least. Problem here is that once you drive an amp into clipping you are now producing harmonics composed of higher frequencies 'manufactured' from the original signal and those harmonics are at much higher power levels. Tweeters meant to absorb 10 watts are now facing 50 or more. Get your tweeters repaired or replaced and buy a more powerful receiver - or listen to quieter music.


Thanks for the replies -- I double checked the tweeters and they are not working. They were working after I repaired them- I replaced the wire from the diaphragm to the terminal, as per previous threads..... I'm wondering of they are blown from being underpowered at loud volume. I did crank up the 20 watt Sansui a little loud which did produce some distortion. (needs a recap)

[DerekTheGreat]

Hate to say it after the fact but it's actually easier to damage a speaker rated at 100 watts with a 20 watt amp than with a 200 watt amp...

Can confirm. I routinely feed my L150A's 600 watts and they're happy. They were not happy with what I started out with, which was only 100 watts.

[Mikesignal]

I ordered new tweeters . Will look for a receiver or amp with more power before using them again. Thanks for the replies/advice.

[ARIKIP]

The L100T definitely likes some decent power. My first L100Ts i purchased in 1990 were run off a 200W RMS/Ch Perreaux power amplifier and it was perfect. The bottom end/Bass capabilities of the 2214H woofer is very impressive and requires that power to control them. They are still an excellent speaker today and deserve a decent bit of Amplification behind them.

[BMWCCA]

I ordered new tweeters . Will look for a receiver or amp with more power before using them again. Thanks for the replies/advice.
Just don't play it so loud until you have adequate power.